Turnstile or like mechanisms

ABSTRACT

A reversible pawl particularly applicable to rotary toothed members associated with turnstiles is provided not only with the normal return spring tending to position the pawl neutrally but a secondary spring preferably with high damping characteristics, so arranged that in a rest position the pawl is biassed in one sense of operation or the other according to which was the last operational movement of the toothed member.

Elite States Patent [191 Collins TURNSTILE OR LIKE MECHANISMS [75]Inventor: Terence John Collins, Redhill,

Surrey, England [73] Assignee: Tiltman Langley Limited, Surrey,

England [22] Filed: Sept. 17, 1971 [21] Appl. No.: 181,314

[30] Foreign Application Priority Data Sept. 3, 1970 Great Britain42,262/70 [52] 11.8. CI. 74/527 [51] Int. Cl 605g 5/06 [58] Field ofSearch 74/527, 577 R, 577 S [56] References Cited UNITED STATES PATENTS1,110,802 9/1914 Ledeboer 74/577 S 1,496,184 6/1924 Stroh 74/17.5

[451 Aug. 28, 1973 1,250,179 12/1917 Hughes 74/l7.5

903,536 10/ 1 908 Benner 3,327,543 6/1967 Nirenberg 74/17.5

FOREIGN PATENTS OR APPLICATIONS 736,280 6/1943 Gennany 74/577 S 361,3684/1938 Italy 74/l7.5

Primary Examiner-Charles J. Myhre Assistant Examiner-R. I-l. LazarusAttorney-Nelson l-l. Shapiro et a1.

[57] ABSTRACT A reversible pawl particularly applicable to rotarytoothed members associated with turnstiles is provided not only with thenonnal return spring tending to position the pawl neutrally but asecondary spring preferably with high damping characteristics, soarranged that in a rest position the pawl is biassed in one sense ofoperation or the other according to which was the last operationalmovement of the toothed member.

5 Claims, 3 Drawing Figures TURNS'IILE R LIKE MECHANISMS This inventionrelates to a reversible pawl-controlled mechanism in which a toothedrack or like element is movable through a certain range of movement or aseries of ranges, and within any one range is pawlcontrolled so as to beirreversible, being reversible between the end teeth of two consecutiveranges.

More particularly the invention is concerned with reversible turnstilemechanism in which a rotatable element has to be pennitted to turn inone sense of direction or the alternative sense so as to permit oneperson through it at a time the turnstile moving from one station orrest position to the next consecutive station. In such a turnstile therequirement arises that it should be reversible in sense of rotationwhen it is at rest at any one station. The invention has as itsprincipal aim to eliminate a certain amount of malfunctioning which canbe inconvenient and may be even dangerous, which will be enlarged uponbelow.

Application, Ser. No. 868109 now U.S. Pat. No. 3,602,350 describes andillustrates pawl-control mechanism embodied in turnstile mechanism andoperating in accordance with the foregoing statement. The presentinvention is concerned with a refinement relating to the pawl itself insuch apparatus. The description in the foregoing Patent Application isintended to be embodied herein by reference and it would therefore berepetitious to restate it in detail.

Turnstiles particularly as they may be used in public transport systemsmust be so contrived to minimize any human risk, inconvenience, or delayas far as possible. It is a defect of some existing mechanism that sucha check pawl may overcarry when it is reached by a rest position and jamthe next phase of rotation. In a turnstile this can be inconvenient andeven dangerous, as the following narrative of an incident will show.Assume that a stream of passengers is passing through a turnstile, eachone hard on the heels of the one ahead. Each person may reasonablyassume that when he enters the turnstile it will be free, so he needhardly check his gait; but if in fact the turnstile is jammed when heenters it he may fall over it or at least be quite shocked by severeimpact with the turnstile. This can arise if the check pawl jams theturnstile. The invention is concerned to obviate this inconvenience orrisk.

According to the invention there is provided pawl controlled mechanismin which a series of teeth or abutments is to be engaged by a pawl whichis reversible in its operative sense of direction which series isinterrupted by one or more gaps to provide for pawl reversal, in whichthe pawl is pivotted for reversal and is resiliently urged towards aneutral position, further characterised by provision of second resilientmeans to act on the pawl with bias alternatively in one sense or theother of operational direction. In mechanism characterised as above thesecond resilient means is so constituted as to be substantially dampedin its effect on the pawl; preferably this is accomplished by making thesecond resilient means in the form of a leaf spring made of a resilientsynthetic plastics material with high internal damping of which atypical example is a Du Pont material Adiprene" which is a syntheticplastics polyurethane material in the nature of a synthetic rub ber.However, it is within possibility that where a plastics material isundesirable the second resilient means may be in the form of a laminatedleaf spring with frictional interfaces to increase its self-dampingproperties.

A preferred form of the invention will now be described with referenceto the accompanying drawings. In these FIG. 1 is a scrap view which canreadily be identified with FIG. 1 in the aforementioned application;where possible the same references are used.

FIG. 2 illustrates how the invention modifies the construction of FIG. 1and shows the pawl in one rest position and FIG. 3 is a view similar toFIG. 2 showing the alternative rest position.

In these Figures the toothed element of which the movements are to becontrolled by the pawl is the rotatable member 1 with peripheral notches2 and three peripheral gaps 4 disposed at around the member 1. Themember 1 is rotatable with the turnstile itself in order to control thelatter. A double-acting reversible pawl 5 is shown mounted on a pivotspindle 6. The pawl is biassed to a neutral mid position as drawn inFIG. 1 in which the nose of the pawl 5 lies in one of the gaps 4. Thenose 5A of the pawl 5 has two angled corners 5C so adapted that one ofthem will engage notches 2 as the turnstile and therefore the member 1rotates. The pawl 5 is therefore operative in regard to either sense ofrotation of the turnstile. This ensures that starting from one of the120 stations (as in FIG. I) in whichever sense the turnstile is rotatedso it is prevented from being turned from any substantial anglebackwards until the next gap 4 is entered. It should be observed thatFIG. 1 is in fact unreal (as will be explained shortly) but it is hereused mainly to show the close similarity of the present invention tothat of the quoted Applications. The pawl is influenced towards the midposition in which it appears in FIG. I by a tension spring 128 which istensed between a fixed post 12D and a pin 12E carried by the pawl 5.

By the invention there is added the second resilient means which is toact on the pawl in the form of a leaf spring 10 which is anchored at thepin 12D and which bears (when the pawl is at rest) on one side or theother of the pin 12E. Which side it bears on is determined by the senseof operation direction last experienced by the pawl. Thus in FIG. 2 thearrow 21 is intended to indicate that the member I has last operated inan anticlockwise direction, i.e. one in which the pawl 5 would have beenrotated through a considerable clockwise angle from the position drawn.When in that operation position it willbe clear that the pin 12E wasquite out of contact with the leaf spring 10. Such contact was, however,resumed when the pawl 5 fell into its rest position as shown in FIG. 2in which position the leaf spring 10 contacted the right-hand side ofthe pin 12E. In that situation although the spring 128 tended to locatethe pawl S in a strictly neutral position the opposing'force due to thespring 10 causes the pawl to be slightly biassed in its position. i.e.to take up a position of rest as shown in FIG. 2.

When, however, the direction of the arrow 21 is reversed (that is themember 1 has been turning clockwise) then of course the pawl 5 will havebeen operatingin the sense contrary to the foregoing and the pin 12Ehaving pushed its way past the spring 10 will return to the contraryside of the spring, the final rest position of the pawl 12 now being asseen in FIG. 3.

The high internal damping of the spring 10 brings the pawl 12 to rest asit approaches each rest position in a gentle manner so that the pawldoes not tend to overrun by its own momentum. This therefore ensuresthat the previously narrated type of incident will not occur. At thesame time the operation is of course quick enough to take place betweenthe passage through the turnstile of one person and the next.

It will thus be seen-that by the addition of the second resilient means,that is to say the leaf spring malfunctioning of the kind abovementioned is avoided.

I claim:

1. A pawl controlled mechanism comprising a pawl and a ratchet, saidratchet having a series of teeth interrupted by at least one gap andbeing supported for reversible movement, said pawl being supported forreversible pivoting movement and being positioned to engage said teethto prevent substantial movement of said ratchet in one direction or theother and to enter said notch to permit reverse movement of saidratchet, and first means for resiliently urging said pawl to a neutralposition with respect to said ratchet, said mechanism being furthercharacterized by the provision of second means for resiliently biasingsaid pawl from its neutral position in one sense or the reverse sensewhen said pawl enters said notch depending upon the previous directionof movement of said ratchet.

2. Mechanism according to claim 1 in which said second means has meansfor damping its effect on the movement of said pawl.

3. Mechanism according to claim 1 in which said second means is a leafspring made of a resilient synthetic plastic material with high internaldamping.

4. Mechanism according to claim 3 in which said first means is a tensionspring and in which said leaf spring is positioned to engage said pawlwhen it enters said notch and urge said pawl in one sense or the reversesense and is positioned to be disengaged from said pawl when the pawlengages said teeth.

5. Mechanism according to claim 1 in which said pawl has a nose ofrectangular cross-section with two corners for alternating engaging saidteeth depending upon the direction of movement of said ratchet and inwhich said notch has a pair of parallel sides adapted to engagecorresponding corners of said nose.

1. A pawl controlled mechanism comprising a pawl and a ratchet, saidratchet having a series of teeth interrupted by at least one gap andbeing supported for reversible movement, said pawl being supported forreversible pivoting movement and being positioned to engage said teethto prevent substantial movement of said ratchet in one direction or theother and to enter said notch to permit reverse movement of saidratchet, and first means for resiliently urging said pawl to a neutralposition with respect to said ratchet, said mechanism being furthercharacterized by the provision of second means for resiliently biasingsaid pawl from its neutral position in one sense or the reverse sensewhen said pawl enters said notch depending upon the previous directionof movement of said ratchet.
 2. Mechanism according to claim 1 in whichsaid second means has means for damping its effect on the movement ofsaid pawl.
 3. Mechanism according to claim 1 in which said second meansis a leaf spring made of a resilient synthetic plastic material withhigh internal damping.
 4. Mechanism according to claim 3 in which saidfirst means is a tension spring and in which said leaf spring ispositioned to engage said pawl when it enters said notch and urge saidpawl in one sense or the reverse sense and is positioned to bedisengaged from said pawl when the pawl engages said teeth.
 5. Mechanismaccording to claim 1 in which said pawl has a nose of rectangularcross-section with two corners for alternating engaging said teethdepending upon the direction of movement of said ratchet and in whichsaid notch has a pair of parallel sides adapted to engage correspondingcorners of said nose.